Question

Calculate the number of normal modes of vibration for the H2O compounds.

Answer 1

Vibrational modes of the H2O molecule

Density functional theory can be used to calculate vibrational frequencies of molecules, e.g. either in the gas phase or on a surface. These results can be compared to experimental output, e.g. from IR-spectroscopy, and they can be used to figure out how a molecule is bound to the surface. In this example we will calculate the vibrational frequencies for a water molecule.